This invention relates to electronic computing scales of the type utilized for calculating and displaying postage or other shipping rates according to the weight of an item.
To be found within the prior art are many kinds of computing postal scales of an electronic nature incorporating digital circuitry, microprocessors, microcomputers and the like for electronically comparing weight with rate data stored electronically to determine the postage or other shipping charges.
Many of these electronic scales have been very complex, utilizing substantial electronic memory to store the extensive data, rate scales, zone charges and so forth which must be taken into account in determining the ultimate postage, shipping rate or charges, bearing in mind that postage rates may vary not only with weight but also with size, distance sent, and the type of shipment. Thus, there are many classes of mail service, including first class, priority mail, third class, parcel post, book rate and many other specialized rates or services, including the rates of commercial shippers, such as United Parcel Service and express mail services. Because of the many different charges, rates and services, the amount of data to be stored electronically is very substantial and requires the provision of dedicated memory which has been typically realized in the form of preprogrammed digital memory devices.
Various controls and data input may be required for existing electronic scales to allow selection and programming for these various parameters. When complicated control or data entries are required, there is a substantial chance for operator error since the operator must accurately select the proper data, code or other information to be recalled from memory, or key in specialized data, to be correctly processed by electronic computation.
A further serious shortcoming of existing electronic computing postal scales is that they are not readily and easily adjusted for new postage rates, shipping rates or other charges as they may be imposed or may occur.
In this regard, it is typical in the design of such electronic postal scales to use such digital devices as programmable read-only memories (so-called PROM's) which must be removed and replaced by differently programmed devices whenever there is a change in the postage rate, shipping charge, scale or other cost factors which are to be taken into consideration.
Because of the cost and complexity of such prior art devices, they have had to be sold at prices which are typically too high for many small businesses to justify their purchase.
Accordingly, it is an object of the present invention to provide an apparatus for electronically weighing mail and other packages and automatically and accurately determining and displaying the postage or other shipping charges for such items.
It is also an object of the present invention to provide such apparatus for providing accurate digital display of the weight of the item in various possible units of measurement by displaying the units in conveniently interpreted decimal increments of such units.
It is an object of the invention to provide such apparatus for providing automatic display of the cost of shipment of items weighed by the unit in various possible modes of service and rates, including first class mail, priority mail, third class, parcel post, book rate, library rate, international air letters, express rates and commercial shipping rates, among many others.
A related further object of the invention is the provision of such apparatus which allows easy user selection of the service or category of postage or shipping charge to be displayed without potential for confusion, keying in of improper data, or otherwise introducing operator error.
Yet another object of the invention is to provide such apparatus which permits very easy adjustment or updating of the postage or other shipping rates without necessarily requiring replacement of digital memory devices or similar circuitry.
Another object of the invention is the provision of such apparatus which allows user programming for display of the cost for special shipment services or other specialized rate displays, such as, for example, the display of cost for shipment of parcels to foreign countries by air, sea or other modes of shipment, and for shipment by special shipment services, such as express package shipping companies.
As object of the invention is also to provide such apparatus which will display the cost of postage in conveniently visualized increments of postage so that users of postage stamps, for example, can apply the correct number of stamps without resort to mathematical determination.
Among still other objects of the invention may be noted the provision of such apparatus which prevents a display from being provided until an item is being weighed; which causes indication of an overweight display; which provides signalling of an underweight condition; i.e., if an item is removed after weighing is initiated; and which will tare out the weight of objects, such as trays, packages or the like bearing items to be weighed, which objects are not to be taken into consideration during weighing.
It is yet another object of the invention to provide such apparatus which changes the weight display according to the type of service or category of weighing to be undertaken, e.g., which will automatically change from pounds to ounces to ounces and tenths of ounces, whereby the weight display is always correlated with the rate display.
Among other objects of the invention may be noted the provision of such apparatus which is electronic in character and microprocessor controlled; which utilizes coded logic for the display of shipping or mailing costs; which automatically computes weights regardless of the units of measurement; which provides rate display which is unaffected by extraneous power conditions such as electrical noise and static electricity; and which utilizes electrically nonvolatile memory.
Finally, it is to be noted as being among the objects of the invention the provision of such apparatus which is extremely easy to utilize, requiring minimized interpretation and avoids confusion or misinterpretation so that it may be utilized readily by unskilled personnel with a minimum of possibility for mistake or confusion; and which is of extreme simplicity and consequent low cost.
Briefly, the new electronic scale computes and displays postage or shipping rates and displays also actual weight in chosen increments of items weighed by a platform atop the scale enclosure. A weight sensor provides an analog signal representing item weight. This signal is converted to a digital signal and provided to a computing circuit having a microprocessor for computing weight and rate signals corresponding to the digital signal. Separate weight and rate displays display total weight digitally and display also the actual cost of shipping or postage. An encoded rate selection device is readily and selectively usable with, and replaceable with respect to, said enclosure allowing the user to select a desired predetermined postage or shipping rate schedule, or structure. Detector means decode the rate selection device encoding for computing of weight and rate signals only according to this predetermined schedule.
Other objects and features will be in part apparent and in part pointed out hereinbelow.